1. Field of the Invention
The present invention relates to a gas turbine engine, and more specifically to a gas turbine engine having a bypass fan.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Gas turbine engines exist is sizes from very small—micro turbines—to very large, such as industrial gas turbine. In an aero engine, it is beneficial to reduce the size of the gas turbine in order to fit in a smaller space and to reduce the weight. To reduce the weight and size, the diameter of the rotating blades must be reduced. However, when the diameter of the engine is reduced, the rotational speed of the engine must increase in order to provide the same performance. One of the design factors that limit the diameter or an engine is the material properties of the rotating parts such as the blades. The high rotational speeds produce high centrifugal forces that may exceed maximum design parameters.
U.S. Pat. No. 3,262,635 issued to Smuland on Jul. 26, 1966, FIG. 2 shows an integral turbine blade 34 and bypass fan blade 35 in which the two blades are formed of one piece. The size of this integral blade can be reduced only so much until the higher rotational speeds required would exceed the maximum material properties and the blade would break or plastically deform. Both the turbine blade and the fan blade is made of the same metallic material since they are one piece.
Thus, there is a need in the art of gas turbine engines to provide for a smaller integral turbine and fan blade that can operate at higher rotational speeds and still withstand the forces without damaging the blade. It is an object of the present invention to provide for a reduced weight turbine fan blade that will improve performance by reducing weight and allow for higher rotational speeds of the turbine by providing for a stronger turbine fan blade. It is another object of the present invention to provide for a turbine fan blade that can be easily assembled and installed onto a rotor disk of the gas turbine engine.